This session aims to bring together latest insights from experimental and field-based studies on processes occurring in the Earth’s mantle. Examples of possible topics include, but are by no means limited to, studies of the trace element distribution between minerals, fluids and melts at high pressure and high temperature, phase relations at pressures covering the whole mantle, constraints on mantle redox state and its evolution with time from natural and experimental studies, and field-based studies of exposed mantle sections. We are particularly interested in studies that attempt to link experimental studies with observations on natural samples.